Agent Orange and dioxin-induced myeloid leukemia: a weaponized vehicle of leukemogenesis

Agent Orange (AO) was the dominant weaponized herbicide employed by the United States (US) military during the Vietnam war. AO, however, was found to be regularly contaminated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic dioxin known; furthermore, AO was commonly diluted in the field with other aromatic hydrocarbons to assist with delivery mechanisms. Unbeknownst to the US military and the millions exposed, these events have likely contributed to the development of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) that has affected many veterans. Null studies regarding an association between AO exposure and AML/MDS are limited in their methodology and application. The acknowledgement that the known carcinogen TCDD was a contaminant in AO when paired with a strong biological plausibility for its leukemogenicity and an observed increased risk of AML/MDS in TCDD-exposed individuals should suffice to establish causal association and that veterans to whom this might apply should be awarded appropriate indemnity.